Spectroscopic Basis of Carbonyl Photochemistry. I. The Role of Excited-State Geometry in the Photodecomposition of Formaldehyde

The photochemistry of formaldehyde is correlated with its spectroscopy within a molecular orbital framework. According to the picture, photodecomposition arises from one electron population of a pair of C<H2 antibonding orbitals, one of which is H–H bonding and yields H2+CO and the other H–H antibonding yielding H+HCO or 2H+CO. These orbitals are populated in singlet states by radiationless transitions from the nonplanar 1(n, π*) state.